Advertisers prefer Instagram to Twitter for two main reasons

Instagram has overtaken Twitter as the preferred platform for social media ad campaigns, according to a new study by Comcast-owned STRATA.

The study polled 83 U.S. ad agencies on which social platforms clients preferred for their campaigns, and 63% selected Instagram as their most likely choice, compared to just 56% for Twitter. YouTube placed ahead of Instagram at 67%, though Facebook blew all of its competition out of the water at 96%.

Notably, Snapchat was not included in the study.

Instagram has eclipsed 200,000 monthly active advertisers, and Twitter recently stated in a letter to shareholders that that it had 130,000 active advertisers.

There are two reasons that advertisers now prefer Instagram. In the last three years, Instagram has consistently ranked near the top of social networks among teens, while Twitter's relevance to this demographic has declined, according to Piper Jaffray.

Instagram also surpassed Twitter in users when it hit 400 million monthly active users in September, as Twitter's user growth has slowed significantly since 2014. Twitter now has 310 million active users, slightly more than the 302 million users it had in the first quarter of 2015.